Pneumatic control apparatus



May 23, 1939- A. DEWANDRE PNEUMATIC CONTROL APPARATUS Filed Feb. 4, 1937 FIG. 1.

l l l E El 24 @L il" wane/f@ /N veA/fw Patented May 2 3, 1939 PNEUMATIC CONTROL APPARATUS Albert Dewandrc, Brussels, Belgium, assigner to Servo-Frein Dewandre Socit Anonyme, Lige,

Belgium Application February 4, 1931, serial No. 124,096

In France February 7, 1936 1 Claim. (01. 121-38) My invention relates to a pneumatic apparatus for controlling at a distance the displacement of a mechanical member.

In certain apparatus of this kind wherein use is made of a cylinder with driving piston actuated by compressed fluid in order to control the displacements of some mechanical member, it is sometimes difficult for the operator to ascertain by inspection whether the' duration of the action on the fluid distributor has been sufficient in order to permit the piston to eiect a determined displacement particularly when the driving cylinder has a certain volume.

The object of the present invention'is to establish an apparatus wherein the amplitude of displacement of the driving piston is independent of the duration of the action oi' the operator on the uid distributor. l

According to my invention a distributor of compressed uid, remotely controlled is, upon its actuation, locked in its open position and is subsequently automatically unlocked with closure of the said distributor whenA a driving piston actuated by the delivered fluid and acting on the mechanical member to be displaced has experienced a displacement of predetermined amplitude.

'Iwo forms of embodiment of the device according to the invention will be described below by way of example only with reference to the attached drawing, in which: v

Figure 1 is a diagrammatic view in section of the apparatus with mechanical unlocking of the A distributor;

Figure 2 is a view similar to Figure 1 showing a modication of the device with pneumatic unlocking of the distributor.

Fig. 3 is a, fragmentary sectional detail showing the valve and latch in operative position.

Inthese gures the fluid distributor presents a body 5 in which is arranged a chamber 6 in the extension of which is formed a cylinder 1 closed at its outer end by a plug 8 and communicating by an annular recess 9 with an orice I0 leading into the conduit Illa connecting the distributor to the source of compressed iluid 45.

In the cylinder 1 slides a piston or valve` II carrying at its head a packing I2 of resilient material resistant to the actionA of oil, the said piston presenting on its cylindrical surface longitudinal grooves I4 throughv which ows the fluid under pressure intended to act behind the piston in conjunction with a spring I5 in order to.apply the packing I2 hermetically on vits seat I3 and to normally close all communication between the source of uid and the chamber 6..

A rod I8 secured axially in the head of the piston Il extends through the chamber 6 and is connected to a valve I1 sliding in a bore I8 provided in the extension of the said chamber 6.

This valve I1 is provided with a packing I9, preferably of resilient material', resistant to the action of oil intended to abut on an annular seat 20 provided in the body 5.

A cylindrical portion 2| oi diameter less than the valve I1. connects the latter to any type of control member.

This member is preferably a piston 22 or the like sliding in a cylinder 23 formedV at the end of the body 5, the bottom of this cylinder being closed by a plug 24 into which leads a conduit 25 connected to a distributor of compressed iluid 46 arranged withinreach of the operators hand and connected to the source of fluid 45 by means of the conduit IlIb..

In a bore 26 arranged perpendicularly to the body 5 of the distributor and traversing the latter from one end to the other slides a bolt 21 comprising at one of its ends a cam 28, and at its other end a guiding piston 28, the body of this bolt presenting a constricted part in which is arrangedan opening 30 permitting the easy passage o! the valve I1.

'I'his bolt is subjected to the action of a spring 3| in such a way that when the valveI1 is displaced n order to abut on its. seat 20 the -bolt 21 is pushed upwards so as to engage against the shoulder 32 formed behind the valve I1. y

An opening is provided at 33 in the body 5 in order to put the chambers I8 and 6 in communication with the atmosphere.

A conduit 34 connects the chamber 6 to a cylinder 35 provided with a piston 38 of which the rod 31 presents, at its end, an inclined surface 38 intended to operate on the cam 28v in order to disengage the bolt 21 when thel piston 36 upon its displacements arrives at the end of the stroke.

'I'he latter piston moves against the opposing action of a spring 39 or of any other opposing means provided in the mechanical member (not shown) controlled by the said piston rod.

The operation of the apparatus is as follows: When the operator acts for a short time (a. fraction of a second is suiilcient) on the control distributor 4G, the iluid under pressure led through the conduit 25 into the cylinder 23 of verysmall capacity, pushes back the piston 22 in order to cause the valve I1 toabut on its seat 20, closing the aperture 33' and opening the 4, valve I I, while the bolt 21.under the action of locking the valves in this new position.

The uid under pressure led from thesource 45 by the conduit I0a caniiow through the chamber 6, the conduit 34, and passes into the cylinder 35 pushing back the piston 36.

When the latter arrives at the end of its stroke the inclined surface 33 of the rod 31 operates on the cam 28 unlocking the valves I1 and Il and causing them to return to their original position under the'action of the spring I5, and closing communication with the source of fluid and opening communication with the atmosphere.

The air under pressure contained in the cylinder 35 can then escape to the atmosphere through the conduit 34, the chambers 6 and I3 and the orice 33, the piston 36 returning to its position of rest under the action of the spring 33.

It is to be noted that the bolt 21 must not necessarily be actuated directly by the rod 31 of the piston, but can just as well be actuated by an intermediate member provided with a cam, an inclined surface or similar means against which the piston or itsrod would operate at the end of the stroke.

In the modiiication shown in Figure 2 the apparatus is diierentiated only by the feature that the unlocking of the distributor is obtained pneumatically.

For this purpose the bolt 21 presents at its upper part a piston 40 sliding in a pump chamber 4I formed in the body 5 closed at its end by a plug 42.

A conduit 43 connects the chamber 4I to the cylinder 35 in such a way that when the iluid operates and displaces the piston 36, the latter in arriving towards the end of its active stroke uncovers the orifice of the conduit 43 in order to permit the iluid under pressure to pass, into the chamber 4l and to push back the piston 43 the spring 3|, engages behind the shoulder 32 against the opposing action of the spring 3|, thus operating the unlocking of the valves.

What I claim is:

In a pneumatic apparatus for the remote control of the displacement of a mechanical member by means of an auxiliary driving apparatus, in combination with a source of pneumatic iluid, a cylinder for the said auxiliary driving apparatus, a piston in said cylinder, a iiuid distributor. valves in the said distributor for being displaced against the opposing action of resilient means and for controlling the communication of the said auxiliary driving apparatus with the source of fluid and with the atmosphere, a driving rod for said valves, a groove provided in said driving rod, a piston integral with the said driving rod for sliding in a cylinder provided at the said distributor, a remote manually controlled distributor to open the connection between the last said cylinder and the source of fluid, a bolt subjected to the opposing action of a spring and located transversely with respect to the said driving rod for automatically engaging the groove provided in the latter when the said valves are brought into their position for delivery of iluid to the said auxiliary driving apparatus, a piston integral with the said bolt, a cylinder integral with the distributor and having the last said piston slidably mounted therein, an aperture provided at the predetermined point, of the cylindrical wall of the auxiliary driving apparatus, a conduit opening into the said aperture to connect the said auxiliary motor to the last said cylinder for opening the communication of the latter withi the iiuid delivered into the cylinder of the auxiliary driving apparatus and for automatically disengaging the said bolt when the piston of the said auxiliary driving apparatus has eiected a predetermined displacement and uncovers the said aperture.

ALBERT DEWANDRE. 

